


Sine Qua Non

by dreamlittleyo



Category: Supernatural
Genre: Explicit Sexual Content, First Kiss, First Time, Jealousy, M/M, Sexual Content, Sibling Incest, Wincest - Freeform, Wordcount: 1.000-5.000, Wordcount: Over 1.000
Language: English
Status: Completed
Published: 2011-04-17
Updated: 2011-04-17
Packaged: 2017-10-18 05:28:40
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,725
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/185528
Author URL: https://archiveofourown.org/users/dreamlittleyo/pseuds/dreamlittleyo
Summary: <blockquote class="userstuff">
              <p>Dean's about to get lucky. Sam interferes.<br/></p>
            </blockquote>





	Sine Qua Non

Night finds them in Sioux Falls, South Dakota, with a dead Hodag some seven hours behind them and a meet-up scheduled with Bobby for first thing tomorrow morning. They're unwinding in the meantime, and Sam would just as soon be watching bad TV in their room with a six pack to split between them, but this is the next best thing.

The bar is smoky-dark, and full of chatter so loud that the juke box's heavy beat is barely audible from its spot across the room. They've got a tall booth in the corner, and a couple of fresh beers between them—a small but growing collection of empty bottles scattered across the table. Dean's been eyeing up the hard liquor behind the bar like he's contemplating shots, but they both know better than that. This brief moment of respite is an illusion at best. They can't afford to let their guard down these days.

"What do you think?" Dean asks, and Sam realizes he's been zoned out and staring for god only knows how many minutes. His cheeks flame, but they're already warm from the light, pleasant buzz of the local brew they've been drinking.

"About what?" he asks, wondering if he missed something or if this is just one of Dean's more random non sequiturs. Dean's not looking at him like he thinks Sam is crazy, though. He looks relaxed, and amused and a little bit teasing—oddly illuminated in the gold and green light of the bar—but not impatient, which means Sam probably hasn't missed anything vital.

"About the ladies at the bar," Dean says, eyes cutting away from Sam to the subjects at hand. "I'm inclined to call dibs on the redhead, but the one in the blue skirt's not too tough on the eyes."

Sam forces a smirk to his face and does his best to ignore the tight feeling that settles immediately into his chest.

He gets that Dean doesn't share in his freakish wants—doesn't mean the universe has to keep goddamn rubbing it in.

"You could always try for both," he bites out, hoping it only sounds exasperated. Dean chuckles, low and throaty, and the sound goes straight to Sam's gut. He shakes it off and takes another long pull from his beer. Just keeps tilting it back until he's swallowing the last drop, and when he sets the empty bottle down on the table he finds Dean watching him with indecipherable eyes.

"Both would be greedy," Dean says. Then in carefully measured tones, "You want another?"

"No thanks," says Sam. He's starting to feel it a little more than he means to—hates that no matter how bulky he gets, no matter how much bigger and taller and meatier than Dean, he's still the lightweight between them—and it's probably time for a break.

"Suit yourself," Dean shrugs. And then he stands up, which is exactly what Sam _doesn't_ want him to do because it means he's about to make a move. "Try not to get into any trouble while I'm gone," Dean says with a wink, and heads for the bar.

The near end of the bar—the corner where the redhead is sitting—is actually only a matter of feet from their booth, which means Sam can make out his brother's voice, raised to cut through the ragged chatter of the room. He doesn't bother focusing in to try and catch specifics. He's heard most of Dean's lines before. But he also can't stop staring at the back of Dean's head, and he feels pathetic—like some stupid, lovesick puppy with a crush he should've been over months ago—but that doesn't mean he can look away.

The redhead is smiling invitingly, flashing a wide glint of nearly perfect teeth, and fidgeting with the green, sparkling bangles that hang from her left wrist. The conversation is clearly going well, and Sam rolls his eyes and thinks about getting himself another beer after all. One more can't _really_ hurt, and it'd give him something to do with his hands at least. But he'd have to walk right past them to get the bartender's attention, and Dean will know he's uncomfortable, and Sam doesn't particularly want that. He'd rather sit in his corner and sulk, and pray Dean doesn't feel Sam's eyes drilling holes in the back of his skull.

When the song on the jukebox tapers off and dies away, there's a long empty moment where nothing but the rumble of barroom conversation fills the air. It's almost like a moment of quiet, after the loud bass rhythm of the song, and the murmur of Dean's voice is suddenly crystal clear in Sam's ears.

"You sure you're real?" Sam hears his brother say, and he can practically see one side of Dean's mouth curling up in warm supplication. "Because I could swear I made you up inside my head. They don't make girls as perfect as you."

It's not Dean's _worst_ pickup line, but it's pretty goddamn bad, and if Sam had beer in his mouth he would probably be snorting it up his nose right about now. When the jukebox starts in on the next song, Sam keeps his ears focused in on the conversation. He needs the validation of knowing Dean's over-the-top seduction attempt fell flat on its face.

But the girl laughs and leans in to whisper something soft and secret in Dean's ear, and even if Sam can't make out the words, he doesn't need them to read the interested acceptance in the girl's wide, blue eyes. He watches, horrified and appalled, as she sets a delicately manicured hand high on his brother's arm, murmuring something encouraging as her thumb brushes back and forth across the fabric of Dean's t-shirt sleeve.

Sam's pretty sure he owes it to the world not to let this particular injustice stand. Dean's pretty to look at, sure—Sam can see that a hell of a lot better than he should—but that doesn't mean he gets a free pass to toss around lines like _that_ and actually get laid for them. The world is screwy, but it's not that far gone, and Sam stands determinedly and strides forward with purpose.

He doesn't say anything at first. He just steps up close behind Dean's stool, hovering too near and practically plastered along his brother's back. The girl sees him and looks confused, making eye contact and giving him a questioning look. Dean notices immediately and pivots in his seat, leveling a startled look up at Sam. It's an awkward angle with the two of them crowded so close together, but Sam still catches the distinctive flash of ' _What the fuck_?' conveyed in his brother's eyes.

"Dean," he says in greeting.

"Sam," says Dean, matching his tone but obviously confused.

"Don't mind me," says Sam. "Just changed my mind about that beer." And as he leans over the bar to wave down the bartender, he sets a hand on Dean's arm—right above the spot the redhead's hand rested a moment ago. It's just for balance, of course. Balance and a not-so-subtle message that Dean is a taken commodity. By the time Sam straightens with a new beer in hand, the stool beside Dean is empty and the woman is nowhere to be seen.

He takes the vacated seat and manages to hold a straight face for almost thirty seconds before the dark befuddlement shadowing Dean's brow is too much. Sam snickers helplessly into his beer, feeling light and momentarily free from the tight discomfort that filled his chest moments before. Logically there's nothing to stop Dean from trying again, maybe going for the brunette in the blue skirt, but for the moment Sam's not worried about that. He's got his brother's full, irate attention, and when he's finally finished chuckling, he takes the time to order another beer for Dean.

"Not cool, Sam," Dean mutters darkly, grudgingly accepting the fresh bottle and tossing back a swallow. "The hell was that for, anyway? I was _in_." When he looks at Sam again, there's a cautious consideration in his eyes that makes Sam feel shifty and uncomfortable.

"I was doing mankind a service," Sam says, ready to bluster and dissemble until Dean stops looking at him that way. "There's no justice in the world if a line like that gets you laid."

"We already _know_ there's no justice in the world, Sammy," Dean points out—which, okay, touché.

But Sam shakes his head and says, "It's the principle of the thing."

Dean is quiet for a long, uneven moment, and Sam's skin starts to itch with anticipation. He should say something here. Wasn't the point to distract Dean so he stopped looking at Sam like _that_? The soft curiosity in his eyes is making Sam nervous as hell, and he picks absently at the label on the neck of his beer bottle—he suddenly can't think of anything to say.

"And that's the only reason?" Dean asks. For a second Sam thinks he hears something low and dangerous in his brother's voice.

He swallows thickly, trying and failing to ignore the hot thrum of his pulse as it speeds his blood, and finally manages to say, "What other reason would I have?"

The expression on Dean's face calls bullshit, and Sam watches his brother reach for his wallet—watches him pull out and count a handful of bills and slide them across the counter to the bartender. He watches Dean take a long, slow pull from his beer and then set it down barely half finished as he stands from the stool and locks his eyes on Sam.

It's an electric moment, jagged and hot and indecipherable, and Sam stares up into his brother's eyes, trying to figure out when everything shifted. Dean regards him with what Sam's delusional, hopeful brain wants to read as heated intent, and tucks his wallet back into his pocket. Then, with alarming ease, he leans down and in, close enough to make Sam's heart stop.

"I'm walking back to the room," Dean murmurs, lips brushing maddeningly against the shell of Sam's ear. "You want to meet me there, that's your call. I'll be waiting." When he steps back, all Sam can do is stare. And when he moves for the exit with quick, confident strides, all Sam can do for embarrassingly long seconds is watch him go.

It takes Sam almost ten minutes to process the conversation and come to the conclusion that he can't possibly be misinterpreting his brother's intentions. He's heard Dean's husky, seductive voice enough times to know when it's being used deliberately. Sam's ear still tingles with the brushing memory of contact, and his breath feels ragged in his chest. He wants— _god_ , he wants—and he stands so fast he wavers on a head rush.

Even as he strides across the floor and through the exit, it occurs to him that this could be some cruel prank. This could be Dean's revenge for Sam's unwarranted cockblock, no matter how solid the pretextual principle behind Sam's interference.

But his steps swallow the sidewalk in rapid succession, the night air cool and crisp around him, and Sam is more and more sure that's not what this is. Dean would never prank so casually with something that has this much potential to fuck them up. It's one thing to slap Sam's ass in public and call him 'honey'. It's another thing entirely to proposition him privately.

Besides, even if Sam's wrong—even if this is just the world's most convoluted game of gay chicken—he can always laugh it off later. He can play along until Dean cracks, and assuming he can manage to _stop_ , he can gloat and tease and convince Dean it was all just about winning.

He doesn't know what he expects to find when he steps back into the room. His brain has concocted all kinds of insane images by then. Images like Dean lying naked in one of the beds, a sheet drawn up to his waist and red flower petals scattered in a trail from the door. Or maybe Dean standing braced against the far wall, naked and on display for the moment Sam comes through the door, stance wide in invitation. Or hell, maybe Dean will be kneeling in the middle of the floor, shirtless and impatient, with his head bowed and his shoulders tight and his dick hard beneath the fabric of his jeans.

There's no such dramatic scene waiting for him when he walks through the door. No naked Dean spread out in supplication waiting to be claimed.

Just Dean, his brother, sitting on the edge of the far bed. Dean's feet are planted firmly on the floor, his hands clasped between his knees, and his shoulders slump forward in a tense line. It could be anything. Could be a normal night, Sam coming home to find Dean already there, puttering or packing or preparing for the next hunt. Except that there's an eerie silence in the room: no sound of television chatter, no radio or magic fingers or research spread across the small table by the window. Dean is obviously waiting for him.

And the bed he's sitting on is Sam's.

"Dean," says Sam, and his brother raises his head as if this is the first sound he's heard. Maybe he didn't notice Sam come in.

Dean stands in a fierce, fluid motion, but the confident smirk on his face is belied by the wide intensity in his eyes. He doesn't approach, apparently too uncertain to make the first move now that they're here—and Sam supposes that makes sense. Dean's got even less to go on here than he does.

Sam turns away long enough to lock up behind him: deadbolt and chain in place before he steps further into the room and catches Dean in his greedy gaze.

Now that he knows to look for it, he can read the nervous uncertainty in Dean's stance. The nebulous hope flashing in Dean's eyes makes Sam's blood simmer hungrily, and it hits him with the overwhelming force of a speeding semi: _Sam_ is the one with the power here. Dean is the brave one—Dean made the offer—but Sam is the one who holds the next few minutes in his hands.

This is no prank. This is Dean on offer, and Sam knows full goddamn well that he's going to take everything his brother has to give.

He crosses the room as slowly as he can, which is barely slower than a run, really—he's been thinking about this too long to be patient now—and Dean doesn't step back when Sam invades his space. He stands cautious and still as Sam rests a hand at the line of his jaw and tips Dean's head back to really _look_ at him. Dean's throat works in a hard swallow, eyes darting back and forth across Sam's face, and Sam feels his mouth curl into a hungry grin, lips parting to show just a hint of teeth. He sees responding heat flash behind Dean's eyes, and his blood flows south so fast it leaves him lightheaded.

"How do you like it, Dean?" Sam asks, and he barely recognizes the throaty growl of his own voice. "You like it hard? Slow? Sweet? Rough?"

"I like it any way _you_ want it tonight," Dean breathes. Then, in a choppier voice, "You better not be fucking teasing, Sammy. I'll kick your ass if you're planning to work me up and then walk away." The words echo with stubborn bravado, but Sam can hear the genuine fear behind them. He can see in Dean's eyes how terrified he is of giving himself away like this if Sam's not really along for the ride.

And even though he feels a second of temptation to play it out—the power is heady and addicting, and Sam could get high on this feeling of having his brother's heart in his hands—he knows he has to do something to quiet that hurting hint of fear. He's not enough of an asshole to leave Dean wondering when he knows all too well what it feels like on the other side of that fence.

When he kisses Dean, he makes sure there's nothing tentative about it.

Dean's lips are warm, and softer than they have any right to be, and Sam smiles against his brother's mouth when Dean's hands trail up his arms—when Dean's arms circle encouragingly around his neck—when Dean's body all but melts against Sam and the nervous tension vanishes to make way for something dark and hungry and eager.

Proprietary instincts rush through Sam's veins, superheated intent, and his hands close possessively over Dean's hips. He grips tightly, wondering if his fingers will leave obvious bruises. He likes the thought of being able to see his marks on Dean come morning, tangible evidence in the growing light of the sunrise, and he tightens his hold. Hums happily when it makes Dean press even harder against him. And when Dean's lips part in obvious invitation, Sam changes the angle of the kiss just so and slips his tongue into the impossible heat of his brother's mouth.

Dean's body is a wall of stubborn, frantic energy against him, and Sam finds himself rutting against his brother, a maddening chafe of fabric and flesh. He drags Dean's hips forward, slipping a leg between his brother's thighs, and Dean grunts into the kiss. Dean's cock is a line of heat against Sam, and there's too much goddamn denim between them. The friction is riling him, their bodies incapable of holding still, and Sam's sure—so goddamn sure—he could find release this way, but he wants a hell of a lot more, and he's pretty sure Dean does, too.

He stops the only way he can: abruptly. He almost stumbles when he yanks his hands away and takes a sudden step back, and he sees Dean teeter for a moment, unbalanced and confused, eyes locking on Sam with a new flash of question. Sam can practically hear his brother's voice in his head, breathless and needy and irritated as he points an accusing finger and says, ' _No take-backs, Sammy_.' But Dean isn't saying anything. Dean is watching him warily, like he's afraid Sam will cut and run, and Sam feels the same edgy thrill of power hit him.

He squashes it down again and says, "Clothes off, Dean. Before I get impatient and do irreparable damage to your favorite shirt." The shirt Dean's wearing isn't actually his number-one favorite, but Sam knows it's in the top five. Clean, gray, no bloodstains. It's one of Sam's favorites, too. He likes the way it clings to the straight, strong lines of Dean's body.

Sam can see the moment of indecision as it flashes across his brother's face—a split second where Dean doesn't quite know whether to laugh or comply. Thankfully he follows the path to compliance, grasping for the hem of the shirt and pulling it slowly up and off. Sam tracks every inch of bared flesh as Dean's stomach, his chest, his collarbone all become visible. He mistakes the slow pace for hesitation at first, but when Dean tosses the shirt aside and reaches for the button of his jeans, there's a twinkle in his eyes that makes Sam reassess.

So Dean caught him drooling for those gradual inches of skin. So Dean's finally figured out what's what here tonight. So Sam doesn't have sole monopoly on the balance of power after all.

He finds, to his surprise, that he doesn't mind in the slightest.

Dean's movements are a deliberate tease, calculated and measured as he pops the button on his jeans and then slowly, slowly, slowly pulls down the zipper to reveal extra inches of the flat planes of his stomach, and finally the black fabric of the boxers beneath.

Sam doesn't breathe until his brother has finished stepping out of the denim he leaves pooled on the floor, and the sight of Dean standing there in nothing but his amulet and boxers _really_ shouldn't be hitting Sam this hard. Lord knows he's seen it hundreds of times before.

But this is the first time it's been all for him. This is the first time Dean has stood there looking at him like that, goddamn _smoldering_ at him, and Sam flushes hungrily. It's all he can do not to tackle Dean to the bed right this second.

Dean approaches him with new confidence when Sam finally manages to lift his eyes to his brother's face. He steps close and raises his hands to Sam's chest, resting them there for a meaningful moment before attacking the buttons of Sam's shirt with smooth, practiced grace. Sam just stares at him, feeling suddenly famished for his brother's touch, and so goddamn eager, fuck, he's ready to burst out of his skin.

He cooperates when Dean urges him out of his sleeves, and then lifts his arms obligingly when Dean moves to tug Sam's t-shirt up and over his head. He's probably supposed to hold still longer, let Dean reach for his pants, too, but the frantic need beneath Sam's skin is growling impatiently. Dean is close enough to taste, close enough for the aura of his body heat to wiggle past Sam's defenses, and instead of standing still like he's supposed to, Sam growls and drags his brother against him. He grabs blindly for the waistband of Dean's boxers, yanking at them once he has hold, and his blood thrills at the taste of Dean's surprised curse against his lips.

Dean actually breaks the kiss to gasp a loud, startled, " _Fuck_ , Sammy!" when Sam hoists him up and carries him three feet to the nearest bed. They go down in an undignified topple, landing in a sprawl of limbs, but Sam comes out on top, and he pins Dean to the mattress with licks and kisses and claiming hands. Dean obviously doesn't mind. He twists his body cooperatively when Sam moves to divest him of his boxers, and writhes just right when Sam finally—fucking _finally_ —closes his right hand around the hot, heavy weight of his brother's cock.

"Wait," Dean gasps as Sam swipes his thumb over the head. "Sammy, wait, fuck, what about you?" And yeah, Sam's own erection is a straining, uncomfortable pressure in the confines of his jeans, but he's got better priorities right now. He's got Dean laid out and writhing, bucking into his hand, and he can't be bothered to shift his attention just now.

But that's what teamwork is for, and even as he grinds into Sam's hand and cusses up a storm, Dean's getting his fingers to work on Sam's fly. The button and zipper are no match for even his unfocused attention, and Sam gasps and bucks his hips forward when Dean works his strong, sneaky hand past the waistband of Sam's boxers and wraps his fingers around Sam's cock.

" _Yes_ ," Sam breathes, and doesn't let up in his own stroking, pressing rhythm. He wants to kiss Dean again, but he's pretty sure he doesn't have the coordination for it, so he mouths along Dean's throat instead—easy to do, since Dean has his head thrown back on the world's longest moan, leaving the strong, slender line of his neck right there and so deliciously vulnerable. Sam groans and kisses the soft skin just beneath Dean's ear—just above the pulse point—and he doesn't mean to bite down, but then Dean does something _different_ with his hand. Something that makes Sam hiss, and his teeth close on hot, salty skin—which only makes Dean moan louder, so Sam bites down harder. He's careful not to break the skin as he sucks at the flesh between his teeth, worrying at it and claiming it, leaving what he hopes will be a spectacular hickey come tomorrow.

Dean won't be able to hide it, and Sam knows he won't be able to stop staring.

They're both too gone for anything resembling finesse, and Dean comes first, striping Sam's hand and belly and filling the air with a loud, gusty groan. The rhythm he's been providing tapers off, and Sam lets go of Dean's softening dick in favor of wrapping his palm around Dean's hand where it still encircles Sam's stubborn erection. He tugs his boxers down and out of the way, leaving more room to maneuver as he squeezes Dean's fist tighter around his cock and guides him to a faster, rougher pace.

Dean comes down from his climax quickly and takes the hint, shaking off Sam's guiding hand and then repositioning his grip to tug and stroke and pull Sam over the edge. Sam's vision blanks as his orgasm hits him, and he gasps something that might be Dean's name. Feels like maybe he comes forever, Dean's hand a gentler touch now, coaxing him through it.

He comes back to himself in a heap, crushing Dean into the mattress with his full weight, and his head cradled on Dean's sternum like the world's boniest pillow.

He blinks and feels the world shift back into line around him, and Dean's voice is a tangible rumble against his cheek when his brother says, "Hi there."

"Hi," Sam whispers, suddenly terrified that this is some kind of vivid, impossible dream that will vanish at any moment.

"You gonna move any time soon?" Dean asks warmly. "I'm starting to lose feeling in my arm."

"Which one?" Sam asks, still feeling too boggled to process.

"The one you're _lying_ on, jackass," Dean mutters, and just like that Sam knows this isn't a dream. This is Dean, every bit as real as Sam himself, sleepy and breathing heavily and feeling the same mingled heartbeats that Sam finds himself counting.

"Sorry," Sam mutters, and shifts to lie on the mattress beside instead of on top of his brother. His stomach feels sticky and gross, tacky with come, and as soon as he can find his legs, a shower might be a good idea. Maybe Dean will join him.

Dean is watching him now, Sam realizes, half-lidded eyes cataloguing him but carefully guarded so that Sam can't read a single useful thing in his brother's gaze. He thinks it's pretty safe to assume Dean isn't freaking out—they're both still here, after all—but beyond that, he doesn't really know what to think.

"So," he says tentatively. "That was… unexpected."

Dean gives him a sour look and rolls his eyes, shifting onto his side to look Sam full in the face, and finally says, "That's what I like about you, Sammy. You're always so eloquent. Master fucking wordsmith."

"Yeah, well," Sam grumbles. "You're a cranky bitch. So are we okay, or what?"

Dean grimaces and flops onto his back, and with eyes that stubbornly track the ceiling instead of looking at Sam he says, "You tell me, dude. You're the one who's into all this sharing and caring bullshit." Which Sam interprets to mean Dean is as off-balance and surprised as he is, which means neither one of them has any clue what comes next. It should be terrifying.

Sam realizes with a jolt that it isn't.

He wishes he could give his brother the blanket reassurance of words like, ' _Yeah, man, we're fine_ ,' but he doesn't want to make guarantees that could still fall flat and prove disastrous. This is all too new, and Sam doesn't want to jinx it.

So instead of answering, he props himself up on one arm and leans over Dean. He moves slowly enough to broadcast his purpose, and when Dean doesn't try to duck away, Sam gives him the kind of slow, tentative kiss they were both too impatient for an hour ago. He lets it linger, deep and hopeful, and when he finally pulls back, Dean is watching him with careful wonder in his eyes.

"I need a shower," Sam says. He lets the invitation and implication smolder meaningfully beneath the words.

"Yeah," Dean breathes, softer than Sam expects. "Me, too."

When Sam stands and heads for the bathroom—shucking his pants and boxers along the way—Dean doesn't hesitate to follow.


End file.
